Field of the Invention
The present invention generally relates to a method for depositing a dielectric film in a trench of a substrate by plasma-enhanced atomic layer deposition (PEALD).
Description of the Related Art
In PEALD, since a sidewall of a trench of a substrate undergoes less ion bombardment than does a top surface of the substrate, surface reaction at the sidewall is less active than on the top surface, causing a problem that an etch rate of a film at the sidewall is different from (higher than) that on the top surface.
Conventionally, by increasing the process temperature or the like, the quality of a dielectric film (e.g., density, hardness) deposited on a sidewall is improved so that the etch rate at the sidewall can be decreased. However, the improvement is partial, and the problem in different etch rates between the sidewall and the top surface is not sufficiently resolved.
Any discussion of problems and solutions in relation to the related art has been included in this disclosure solely for the purposes of providing a context for the present invention, and should not be taken as an admission that any or all of the discussion was known at the time the invention was made.